A leading theory about Alzheimer's Disease (AD) suggests that toxic plaques of beta-amyloid protein accumulate in the aging brain, destroy neurons, and cause declining cognitive function. This theory has been deeply scrutinized and modified over the past two decades of intensive research.

The notable, but poorly understood role of amyloid has driven both treatment strategies and diagnostic strategies for Alzheimer's Disease. In fact, a great majority of efforts to treat Alzheimer's disease have been based on agents that either slow production of amyloid, alter the form of amyloid, or remove amyloid from the brain. Likewise, many diagnostic approaches have been driven by measures of the amount of amyloid in the brain or spinal fluid.

New research from the Penn Medicine Department of Radiology, published in the Neurobiology of Aging, suggests that the location of amyloid plaques in the brain may be more important that the amount of amyloid in the brain. In fact, it has been widely observed (but as yet unexplained) that many older adults, who died with complete cognitive integrity, were shown at autopsy to have massive amounts of amyloid plaques in their brains. Evidence favoring amyloid location over amyloid burden in diagnosing Alzheimer's disease offers a potential explanation for these puzzling observations.

The amyloid hypothesis has evolved considerably since it was first introduced. This research may offer a further refinement and a better understanding of the complex pathology of Alzheimer's Disease.

Historically, science has tried to answer this question by measuring the duration of concussion symptoms. Often, depending on the severity of the concussing event, symptom such as dizziness, blurred vision, and interrupted sleep are completely resolved within a few days or a couple of weeks.

However, we also know that many injuries, to various tissues in the body, are not completely healed until long after clinical symptoms have faded. This may also be true of injuries to the brain.

In fact, new research from the Mind Research Network in Albuquerque, N.M. supports such thinking. In a paper published in the online edition of Neurology, researchers showed that physical changes to concussed brains persisted for many months after symptoms had resolved.

One implication is that the brain needs longer to heal than the period demarcated by clear symptoms.

A second, and perhaps more important implication, is that brain injury and symptoms of brain injury may not be always correlated. In that regard, the constant, low-impact collisions of many sports may be injuring the brain in ways that are not obvious in terms of symptoms, but are injurious just the same.

For some reason, when Alzheimer's Disease is discussed in the popular press, the discussion often includes a reference to the fact that "there is no cure" for this disease. This is a true statement, but somewhat misleading.

This is misleading because it establishes "a cure" as the appropriate frame of reference for evaluating our ability to fight against this disease.

However, in medicine, we know this is not true. For example, we have no cure for hypertension, but we treat it effectively for most people. Clearly, the "no cure" frame of reference is not the most meaningful perspective on hypertension.

Also, we have no cure for diabetes, but like hypertension, we control it to a large extent for very many years. We have no cure for the common cold, eczema asthma, allergies, migraine, anxiety, heartburn, cancer, osteoporosis, depression, lupus or a thousand other common, and sometimes deadly, medical ailments. The truth is, cures are very rare in medicine.

To be clear, everyone would love to have a cure for Alzheimer's. It would greatly improve the world and eliminate much tragic suffering But "no cure" is not the same as "no treatment", and we should not allow the "no cure" label to fill us with pessimism.

In fact, with an early Alzheimer's diagnosis (prior to the dementia stage), doctors can often delay disease progression through a robust regimen of proper diet, physical activity, tight control of chronic conditions, and poly-therapy with approved drugs.

At present, we should not despair that there is no cure. Rather, we should keep searching for a cure while embracing the reality that, like so many other medical conditions, Alzheimer's must be vigilantly diagnosed in its earliest stages and treated to the best of our current abilities.

The cure may or may not come, but initial treatments have arrived, and better treatments will follow.

We know this intuitively. We feel foggy when sleep deprived, and mentally sharper when well-rested. Understanding why this is true raises three very important possibilities.

New Findings
Research out of the University of Rochester Medical Center (URMC) sheds light on an important brain cleansing process that occurs during sleep in the brains of mice, and presumably, in human brains as well. The study, published in the online version of Science, describes a cleansing process that becomes very active during sleep.

It appears that a process, whereby brain cells contract to create more space between them and cerebrospinal fluid flows through the spaces to remove proteins, is ten times more active during sleep than during wakefulness. From this, we suggest the following three possible conclusions:

1. Caffeine is Not a Substitute for Good Sleep
This research suggests that the mental fog of sleep deprivation may be partially caused by an excess of proteins in the brain. If so, these proteins may be, in some way, interfering with optimal communication between brain cells. While a jolt of caffeine may increase the intensity of signals between brain cells and allow for improved mental acuity, it won't solve the problem of excess proteins that may be gumming up the communication process. In this regard, sleep trumps coffee.

2. Excess Proteins in the Brain may cause Irreversible Damage
As readers of this blog know, a leading theory about the cause of Alzheimer's disease is the accumulation of beta-amyloid proteins in the brain. Given that the brain seems to actively flush proteins during sleep, including beta-amyloid proteins, it is plausible that sustained periods of sleep deprivation could increase the risk of Alzheimer's disease.

3. Sleep Disorders may be Especially Dangerous
If the brain engages in important processes of maintenance and repair during sleep, and these processes prevent long-term progression toward neurodegenerative diseases, then sleep may me even more important to our health than we previously suspected. If you snore, or wake often in the night, speak to your physician about a sleep study.

You cannot accurately diagnose Alzheimer's disease with a smell test. The prospect of doing so makes for tantalizing headlines, but the science does not stand up.

To be fair, the prospect of diagnosing Alzheimer's Disease with a sniff test, including this latest flurry of news based on a peanut butter study at the University of Florida, has a legitimate, scientific underpinning. In fact, many Alzheimer's patients do indeed suffer from impaired smell sensitivity.

However, trying to diagnose Alzheimer's disease based on such a test has two major limitations.

First, many medical conditions cause impaired smell sensitivity, including allergies and normal aging, both of which are far more common than Alzheimer's Disease. So loss of smell sensitivity is certainly not a reliable indicator of Alzheimer's disease.

Second, many Alzheimer's patients retain a sharp sense of smell for many years, so intact olfactory function does not mean that one does not have Alzheimer's Disease.

Stories about smell tests, and their utility as Alzheimer's diagnostics, often get a lot of press. In fact, many experts agree that such stories get more coverage than scientifically merited. It is clear that optimistic stories about medical advances attract an audience, and are therefore interesting to news publishers, but you should read them with full awareness and appropriate expectations.

A peanut butter smell test for Alzheimer's diagnosis is not in our future.

The media have widely reported on a recent study showing that Targretin, an FDA approved drug for treating skin cancer, was effective in clearing amyloid plaques from the brains of mice. Given that the presence of amyloid in the brain is a pathological hallmark of Alzheimer's disease, many were optimistic about the potential for a new treatment.

Alas, the scientific process of duplicating results before accepting them as valid, is an important step in generating new knowledge. In this case, three attempts to duplicate the original findings have all failed. That is to say, no other lab has been able to show a reduction of amyloid in the brains of mice treated with Targretin.

The original study with the positive result was conducted at Case Western University Medical Center and published in the journal Science. In its latest edition, the same journal published a technical comment describing the negative results in three other labs.

Lot's of things that seem obvious, turn out to be either counter-intuitive, or surprisingly complex. For this reason, we often apply scientific methods to "obvious questions". It is a means of verifying that our expectations are actually grounded in fact.

A recent study, published in the British Journal of Sports Medicine, looked at how green spaces affect our state of mind. The small study has gotten a fair amount of coverage in the press and, in some regards, investigates a fairly obvious question.

The research looked at brain activity, as measured with mobile electroencephalography, on 12 subjects as they walked through three distinct environments: a shopping district, a park, and a business district. The findings showed that the subject's brains were least "engaged", or more suited to meditation, in the park environment. Additionally, subjects showed evidence of being more engaged, excited, and frustrated, while passing through the shopping and business districts.

On one hand, it seems obvious that a more tranquil environment allows the brain to disengage and become more reflective. On the other hand, it is always reassuring to demonstrate scientifically that an obvious conclusion is supported with empirical evidence.

My take-away? Maybe a small effort to give the brain a short rest, by dampening down all the stimulation of a busy urban life, is a useful and re-energizing break for the brain. Take a walk in the woods if you can, and cut through the park whenever possible -- your brain might appreciate the break.